Burn 500 Calories in 45 Minutes

About This Workout

You heard right — this circuit cooks, and you'll have the skinny to prove it. We dared top Hollywood trainer Jeanette Jenkins to design a routine that would fry your ass and firm you fast. Result: You'll melt about 500 calories doing her mix of multipart toners and kick-butt cardio. We know, because we put it to the test. Jenkins, who trains A-listers like Kelly Rowland, Pink, and Alicia Keys, led a group of FITNESS readers equipped with heart rate monitors through a session to clock their calorie burn. "This workout gets results because it challenges you at every level," Jenkins says. "Each set maxes out your muscles, while the intervals keep your metabolism stoked on high." Check out her fierce physique as she demos the moves, then get cracking! Have a set of five- to eight-pound dumbbells handy and do the circuit three times through — four if you've got the stamina. Rock this workout three to four days a week for a flab-to-fab transformation this month.

Double Snap Kick

Targets abs, butt, hips, and thighs

Stand with feet staggered, right foot forward, hands in fists near chin.

Bend left knee, bringing heel toward butt as you turn hips to left so that left hip is stacked above right. Leaning your torso back slightly to counterbalance, kick out with left leg, straightening knee with toes pointed.

Without lowering leg, bend left knee again (bringing heel toward butt) and do another snap kick, attempting to kick slightly higher than the first kick.

Triceps Star Plank

Begin on floor in a full plank position, shoulders over wrists, then lower chest toward floor, keeping elbows close to sides. Push up to start.

From there, rotate entire body to right as you move into a side plank. Keeping weight on palm of left hand, lift right arm toward ceiling and balance on side of left foot, stacking hips and lifting right leg to about hip height.

Hold for 1 count, then lower leg and arm as you rotate back to start. Repeat on opposite side. Do 10 reps, alternating sides.

MAKE IT EASIER: Do the push-up on knees; keep bottom knee on floor during side plank.

Reverse Lunge with Punch and Front Kick

Targets shoulders, biceps, triceps, abs, butt, and legs

Holding a dumbbell in each hand, stand with feet hip-width apart, arms by sides.

Lunge back with left leg, bending right knee 90 degrees as you lower left knee toward floor. At the same time, bend elbows to bring dumbbells up to chest level, then extend arms forward to shoulder height in a slow jab motion. (Keep head, shoulders, and torso above hips.)

Stand up, kicking left leg forward to hip height, toes pointed, as you lower arms to sides. Do 15 to 25 reps; switch sides and repeat.

MAKE IT EASIER: Rather than kicking leg forward, bring knee up to hip height.

Cardio Blast

On-the-Spot-Sprint

Run in place as fast as you can, really pumping arms, for 30 to 60 seconds.

Arabesque to Balancing Stick

Lift right leg behind you as you reach right arm out to side and left arm overhead. Lean torso forward slightly and pulse right leg up and down a few inches, squeezing glutes. Do 25 reps.

Continuing to stand on left leg, slowly lean further forward until torso is parallel to floor, extending right leg behind you to hip height and both arms forward overhead. Hold for 1 or 2 counts, then return to standing on left leg. Do 10 reps.

Switch sides, standing on right leg to perform 25 pulses with left leg and 10 balances.

MAKE IT EASIER: Touch lifted leg to floor between balancing poses.

Cardio Blast

Lateral Side Shuffles

From a squatting stance, shuffle to the right 3 steps and touch floor with right hand. Then shuffle to the left 3 steps and touch floor with left hand to complete 1 rep. Do 10 reps.